ShakeAlert Earthquake Early Warning Testing Platform

Deborah E. Smith, Jeff J. McGuire, & Julian Bunn

Submitted September 10, 2023, SCEC Contribution #13251, 2023 SCEC Annual Meeting Poster #020

The West Coast ShakeAlert Earthquake Early warning system has been in operation since October 17, 2019 and has been successfully generating real-time earthquake messages. As the system has been in operation there has been concurrent effort to continue improving the system in terms of both increased warning time and accuracy. In order to assess these proposed improvements, ShakeAlert has a System Testing and Performance (STP) platform. The overarching principle is that proposed changes should improve either the warning time and/or accuracy while minimizing additional complexity and overalerting. Often the performance is a balance of these competing goals, resulting in a complex and nuanced assessment. The assessment is applied to the overall system which includes the aggregate contribution of all the algorithms.

To properly assess the value of proposed software changes, STP replays a variety of waveforms (mainly recordings of moderate to large earthquakes and some synthetic earthquakes) through multiple instances of the algorithm stack. STP also has a set of machines that process real-time data through the proposed algorithm stack for 2-4 weeks minimum as a check of end-to-end behavior for typically smaller events than the pre-recorded waveforms.

Five areas of recent changes to highlight include: 1) Significant improvements to the system as a whole in terms of lengthening warning times, mitigating over-alerting and other effects. 2) In the process of migrating STP testing architecture to the cloud to greatly reduce the amount of time it takes to do a full replay test. 3) Adding helpful features to STP warning time figures. In particular, we are in the process of adding a magnitude threshold and an MMI tolerance. 4) Developing scripts to further automate the System Performance Working Group (SPWG) quarterly reports. 5) Adding ability to handle split events and a geodetic peak ground displacement (PGD) algorithm.

Key Words
earthquake early warning, testing, synthetics, replays

Smith, D. E., McGuire, J. J., & Bunn, J. (2023, 09). ShakeAlert Earthquake Early Warning Testing Platform . Poster Presentation at 2023 SCEC Annual Meeting.

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